Moore, 1944, recognized a second New Zealand population with sufficient anatomical differences to warrant description as Chamaesipho brunnea.

[4]: 317–318 Opercular plates are deeply interlocked with sinuous articulation, and subject to considerable environmental wear, making large variations in individual appearance and shape.

Scutal articular ridge, which in chthamaloids is large central lobe on tergal margin, is rounded.

[6]: 70  The tergum is much narrower than in C. brunnea, with articular margin bearing two rounded relatively shallow re-entrants.

Tergal depressor crests are prominent in both species, with fewer (to about four) in C. columna, versus up to seven in C. brunnea.

[6]: 70 Moore, 1944[4]: 317–320  provides full descriptions of hard- and soft-part anatomy for both juvenile and adult stages of C. columna.

[4]: 320, 324 Unlike nearly all other chthamaloids, C. columna occasionally enters tidal estuaries, but not as far as to encounter brackish or muddy water.